In the machining of metals, it is customary to flood the tool and workpiece with a coolant for the purpose of carrying off heat which is produced during the operation. These coolants are typically employed in combination with various agents having lubricating and extreme-pressure properties for reducing friction, especially in tapping and broaching operations. It has heretofore been the practice to employ for such purposes aqueous compositions containing lubricating agents such as emulsified petroleum or non-petroleum additives. Such aqueous cutting fluids or metal removal fluids should meet several important requirements.
Among the requirements for a satisfactory metal removal fluid are chemical stability under normal operating conditions, corrosion-inhibiting properties for both the tool and workpiece, and absence of ingredients which might be noxious to workers or the environment. It is also important for the fluid to avoid leaving deposits or stains on the tool and workpiece following the machining operation. Other important requirements include avoidance of tacky residues that might interfere with the machining operation and avoidance of excessive foam formation.
Numerous metal removal fluids are known in the prior art. However, there is still a need to provide new compositions capable of accomplishing their intended purpose more efficiently than the prior art fluids.
Davis U.S. Pat. No. 3,256,187 relates to an aqueous cutting fluid comprising the combination of an alkanolamine and an organic acid containing about 6 to 12 carbon atoms per molecule, and an alkenyl succinic anhydride. The anhydride is converted to an amine salt in the presence of triethanolamine and water. This cutting fluid may also contain an alkali metal hydroxide.
Singer U.S. Pat. No. 4,257,902 discloses a water-based fluid that is suitable for metal shaping operations. The fluid contains (a) a major amount of water, (b) a minor amount of sulfur- or chlorosulfur-containing E.P. agent that is water-insoluble and oil-soluble, (c) a minor amount of a water-soluble organic dispersing agent which may be a polyglycol, and (d) at least one water-soluble polymeric thickener.
Vinci U.S. Pat. No. 4,505,830 claims a water-free metalworking lubricant containing a major amount of a lubricating oil, a minor amount of a basic alkali metal salt of at least one acidic organic compound, and a minor amount of at least one sulfurization product of an olefinic hydrocarbon. The synthetic lubricating oil may be a polyglycol or one of the esters of various dicarboxylic acids, including alkyl succinic acids and alkenyl succinic acids.
A principal objective of the present invention is to provide an aqueous composition that functions efficiently as a metal removal fluid.
A related objective of the invention is to provide a method of metalworking, utilizing the claimed composition.
Additional objects and advantages will become apparent to persons skilled in the art from the following specification and claims.